The present invention relates to an overlapping two piece intraocular lens, and more particularly to an artificial intraocular lens for implantation in an eye, e.g in the posterior chamber, after extracapsular removal of the natural lens, wherein the two pieces are independently successively inserted through a minimum size incision into the eye for assembly therein to form the two piece lens, and include a lens body or optic and a separate ring shaped collapsible filament, tension frame therefor containing light masking means for inhibiting light rays directed toward the lens body outer edge portions from being scattered thereby toward the retina after the assembled overlapping two piece lens is implanted in the eye.
For treating conditions such as natural eye lens cataracts, a known eye surgery procedure is to remove the cataracted lens through a minimum size incision in the wall of the cornea of the eyeball, and replace it by an artificial intraocular lens as an internal implant. One surgical procedure involves the extracapsular removal of the natural lens, leaving portions of the posterior lens capsule intact as a positioning site for implanting the intraocular lens in the eye.
U.S. Pat. No. 4,605,409 to Kelman discloses a one piece intraocular lens of the above type, having a small size lens body or optic, flexible position fixation haptics, and deformable masking means, such as laterally disposed flat planar wings temporarily contracted to provide the lens with a reduced girth permitting insertion through such a minimum size corneal incision into an eye. Upon implantation, the wings mask the optic side edge portions to overcome the edge glare effect of otherwise scattered incoming light rays at the peripheral marginal regions of the small size lens, such light masking being achieved by leaving the wing surfaces in rough, unground, condition, or by providing an opaque coating thereon.
U.S. Pat. No. 4,056,855 to Kelman shows a two piece intraocular lens, including an elliptically shaped lens member formed of a central lens body or optic and end tongues, and a separate similarly shaped non-collapsible, continuous closed loop wire frame resiliently self-clampable only to the lens body, once the two pieces are independently inserted through a minimum size corneal incision into an eye for like implantation purposes. The frame ends are arranged in the posterior chamber behind the iris and the lens member end tongues are arranged in the anterior chamber in front of the iris, both serving as position fixation means, while the optic is situated across the pupil. No light masking means of the above type are present.
U.S. Pat. No. 4,596,578 to Kelman shows a two piece intraocular lens, including a generally rectangularly shaped lens body or optic and a separate frame having a similarly shaped noncollapsible split ring formed of cantilever flexible arms for embracingly receiving the optic and also serving as light masking means, and cantilever end limbs as position fixation means, the two pieces being independently inserted through a minimum size incision into the eye for assembly therein. The split ring is needed to permit the flexible arms to be separated for snaking the resulting open ring conformation through the incision and thereafter for enclosing the flexible arms around the optic to assemble the lens prior to implantation.
U.S. Pat. No. 4,704,124 to Shearing shows a multipart intraocular lens whose parts are preassembled as a foldable, interconnected unit prior to insertion into the eye, whereupon the unit is folded onto itself to reduce its girth for insertion, and then unfolded for implanting the lens in the eye. The multiple side by side lens parts are indirectly interconnected by seating their outer margins in a groove of a foldable ring frame part which embraces the lens parts, or by hinge, membrane or outwardly extending strand loop connections directly between adjacent lens parts in frameless units, all without tension connection or overlapping arrangement of the lens parts, or use of the above noted light masking means.
It would be desirable to provide a minimum size intraocular lens for implantation in an eye, following extracapsular removal of the natural eye lens, permitting rapid and efficient lens insertion through the same minimum size corneal incision used to remove the natural lens, and at the same time provide light masking means for the lens body, while utilizing a structurally simple and stable arrangement of parts, readily made at relatively low cost from widely available materials.